Abstract: 【Objective】The Huang-Huai-Hai Plain(HHHP) was selected as the research region in this paper. Regional soil water and nitrogen behaviors were simulated and evaluated by a geographic information system (GIS) based conjunctive simulation model.【Method】 A conjunctive model incoporating soil water, heat, nitrogen behaviors and crop growth was established and validated and then coupled with GIS. The regional distribution of water and nitrogen use efficiency (WUE and NUE), nitrogen loss were studied under the soil, meteorological and rural socio-economical conditions of HHHP from 1999 to 2000 by the GIS-based model.【Result】The inter-physiognomy variations on WUE, NUE as well as soil nitrogen leaching has exhibited significant differences. The multivariate stepwise regression results show that in winter wheat-growing season, nitrogen leaching was significantly positively correlated with nitrogen fertilizer applied (NFA), saturated hydraulic conductivity (Ks) and rainfall and irrigation amount (RIA). WUE was significantly positively correlated with nitrogen fertilizer applied and sunshine hours (SH) and significantly negatively correlated with RIA and Ks. NUE was significantly positively correlated with RIA and SH and significantly negatively correlated with NFA and Ks. 【Conclusion】The regional soil water and nitrogen behaviors of HHHP were affected by the biophysical conditions and farming practices obviously, and their spatial distribution can be simulated and evaluated by the GIS based process model.

Key words: Winter wheat, Huang-Huai-Hai plain, Water use efficiency, Nitrogen use efficiency, Simulation, GIS